Overview of the Massachusetts Bay Transportation Authority

This section describes the makeup and responsibilities of the Massachusetts Bay Transportation Authority.

The Massachusetts Bay Transportation Authority (MBTA) was created in 1964, pursuant to Chapter 161A of the Massachusetts General Laws. The agency provides the following: a rapid transit system, commuter rail services, bus services, ferry routes, and transit services for people with disabilities. According to its website, the MBTA is “one of the largest public transit systems in the country, serving nearly 200 cities and towns and over 1 million daily riders.”

According to Section 7 of Chapter 161A of the General Laws, the MBTA is governed by a nine-member board of directors. This section states,

The board shall consist of: secretary [of Transportation], who shall serve ex officio; 1 person to be appointed by the mayor of the city of Boston; 1 person to be appointed by the advisory board who shall have municipal government experience in the service area constituting the authority and experience in transportation operations, transportation planning, housing policy, urban planning or public or private finance; provided, however, that said person shall not represent the city of Boston; and 6 persons to be appointed by the governor, 1 of whom shall have experience in safety, 1 of whom shall have experience in transportation operations, 1 of whom shall have experience in public or private finance, 1 of whom shall be a rider as defined in section 1 [of the General Laws] and a resident of an environmental justice population as defined in section 62 of chapter 30 [of the General Laws], 1 of whom shall be a municipal official representing a city or town located in the area constituting the authority representing the service area . . . and 1 of whom shall be selected from a list of 3 persons recommended by the president of the Massachusetts State Labor Council.

Not less than 2 of the appointed members shall also be members of the board of directors of the Massachusetts Department of Transportation.

The MBTA is also overseen by the Massachusetts Department of Transportation board of directors, whose 11 members are appointed by the Governor. According to Section 3(d) of Chapter 161A of the General Laws, the General Manager of the MBTA is hired by the Secretary of Transportation and oversees the MBTA’s day-to-day activities. 

Preventive Maintenance of Subway Assets

Performing preventive maintenance (PM) inspections on subway assets is critical for ensuring the safety, efficiency, and reliability of the MBTA’s rail system. Subway infrastructure—including tracks, trains, station facilities, signaling systems, and other assets—operate under high stress and frequent use and are exposed to all types of weather conditions. Over time, wear and tear can accumulate, leading to potential safety hazards, service disruptions, and costly repairs. Regularly performing PM inspections can help identify and address issues before they escalate, improving both the operational lifespan of assets and the quality of service for passengers while reducing the cost and inconvenience of addressing these issues later, when they have grown in severity or complexity.

Visual Inspections of Subway Track

The MBTA’s subway system includes 166 miles of track, featuring five primary lines that link riders throughout downtown Boston. Three of these lines operate as heavy rail³ lines (the Red, Orange, and Blue Lines) while the other two operate as light rail⁴ lines (the Green Line and Mattapan High-Speed Trolley Line). The Red and Orange Lines and a majority of the Blue Line are powered by an electric third rail, whereas the Green Line, Mattapan Line, and a section of the Blue Line use overhead wire systems for power.

The Massachusetts Department of Public Utilities, the federally designated State Safety Oversight agency for the MBTA’s subway operations, has set standards for the inspection of MBTA track. According to the Department of Public Utilities’ regulations, specifically Section 151.11 (2)(a) of Title 220 of the Code of Massachusetts Regulation, visual inspections of MBTA track must be made according to the schedule below.

Type of Track	Required Frequency
Light Rail Passenger-service Track	Three times per week with at least one calendar day interval between inspections
Heavy Rail Passenger-service Track	Twice weekly with at least one calendar day interval between inspections

The MBTA’s Maintenance of Way (MOW) Department is responsible for the maintenance and repair of MBTA track. The MBTA’s enterprise asset management system is programmed to automatically generate work orders every week for visual inspections based on the required frequency mentioned above. During a visual inspection⁵ of MBTA track, inspectors within the MOW Department walk each section of track looking for visible signs of damage or wear, such as cracks, misalignments, or other anomalies. Inspectors use a phone equipped with a software application (separate from the enterprise asset management system) to record inspections and any defects found during those inspections. The software application is equipped with GPS technology, allowing inspectors to mark the location of any defects or other problems they observe during the inspection. Once the inspection is complete, the software application generates a Track Inspection Report that details the results of the inspection. The Track Inspection Report is emailed to the inspector’s supervisor for review. The supervisor attaches the Track Inspection Report to the relevant work order in the enterprise asset management system and closes the work order, indicating that the PM has been completed.

Subway Track Defect Reporting and Remediation

The MBTA uses severity codes to categorize the extent of defects or issues observed on the tracks. These codes help prioritize maintenance and repair actions based on the criticality of the defect and its potential impact on safety, train operations, and infrastructure longevity.

The MBTA’s Track Maintenance Standards establish three severity thresholds for identifying defects in both light and heavy rail lines: green, yellow, and red. Green conditions are those that do not necessarily require immediate remedial action but do need to be monitored. Yellow conditions indicate that maintenance limits have been reached or are closely approaching the threshold for trains operating at normal speed. Remedial action is required for yellow conditions, typically within 30 days, depending on the type of defect. Red conditions represent the highest repair priority and necessitate speed restrictions. These defects often require immediate remedial action and may involve removing the track from service until repairs are completed.

All defects found during inspections are recorded in the MBTA’s enterprise asset management system. When a defect is identified, a service request is created. A supervisor then generates a work order based on that service request. The work order is executed, and the defect is to be repaired in accordance with the specifications outlined in the MBTA’s Track Maintenance Standards.

Inspections of Subway Cars

Periodic vehicle inspection and PM is one of the most important activities for vehicle reliability and passenger safety. These recurring inspections address critical safety components as well as other components that ensure reliability, performance, and passenger comfort.

The MBTA performs PM inspections at predetermined intervals based on mileage or time, which are determined individually for each fleet of vehicles.⁶ Inspection intervals have been developed by the MBTA’s Engineering Evaluation & Quality Assurance Department, taking into consideration the manufacturer’s recommendations, component performance, and MBTA maintenance policies. The inspection process includes checks of both critical systems (e.g., braking, suspension, and structural integrity) and supplementary systems (e.g., lighting, HVAC, and interior condition). These inspections are recorded and tracked in the MBTA’s enterprise asset management system.

Each day, a Periodic Mileage Inspection Report is automatically emailed to forepersons at each MBTA car house.⁷ This report identifies the next rail cars that are due for inspection based on the current mileage for the vehicle. The car house foreperson orders that the appropriate vehicles be temporarily removed from service so that they can undergo the necessary inspection. The car house foreperson assigns repair personnel and creates a work order in the asset management system, indicating the current mileage. Repair personnel complete the inspection and document any defects found (and their corresponding severity codes) on a hardcopy Mileage Inspection Form. Once completed, the Mileage Inspection Forms are sent to the car house foreperson, who reviews the information and inputs it into the asset management system. The hardcopy Mileage Inspection Forms are stored in file cabinets at MBTA car houses. Upon completion of each vehicle inspection, the work order is closed in the asset management system, indicating the PM has been completed. The MBTA’s enterprise asset management system automictically calculates the mileage or date at which the next PM inspection is due.

According to the MBTA’s Equipment Engineering and Quality Assurance Vehicle Inspection Guidelines, the following is the lifecycle management strategy for inspection and PM for subway cars:

Lifecycle Management Strategy	Frequency
Red Line PM Inspections—Number 1 and 2 cars	8,500 miles
Red Line PM Inspections—Number 3 cars	15,000 miles
Orange Line PM Inspections—Number 12 cars	12,000 miles or 90 days
Orange Line PM Inspections—Number 14 cars	15,000 miles
Blue Line PM Inspections—Number 4 cars	7,500 miles
Blue Line PM Inspections—Number 5 cars	12,000 miles
Green Line PM Inspections—Type 7 cars	7,500 miles
Green Line PM Inspections—Type 8 cars	10,000 miles or 180 days
Green Line PM Inspections—Type 9 cars	10,000 miles
Green Line PM Inspections—Presidents’ Conference Committee cars	30 days

Subway Car Defect Reporting and Remediation

The car house foreperson reviews all deferred defects⁸ found during an inspection and assigns a defect severity code to each. As previously mentioned, this information is input into the MBTA’s enterprise asset management system. According to MBTA officials, if the car house foreperson believes that the severity of a defect is different from what was initially recorded on the inspection report, the inspection report should be revised to reflect this assessment. According to the Heavy Rail and Light Rail section of the MBTA Subway Operations Preventive Maintenance Inspection and Documentation Policy, the following are the defect severity codes for subway cars:

Code A (Safety Critical / Hold for Repair)	This status is assigned to defects that would pose an immediate safety threat to the passengers, operators or others, as determined by the car house foreperson. A vehicle with this type of defect is not returned to service until the safety critical / Code A defect(s) is (are) repaired.
Code B (Schedule for Repair) [45 days]	Class B repairs need to be completed within 45 days from the inspection. These defects are not a safety concern but must be addressed in the near term to avoid reducing the vehicle’s reliability. This Class indicates that the vehicle may be returned to service temporarily but is scheduled for repair of the defect in the short term.
Code C (Serviceable)	Code C repairs are for cars awaiting delivery of parts that may take longer than 45 days to deliver. This is assigned to defects that are not expected to have a significant effect on safety or reliability but which are recommended to be addressed to keep the vehicle in a state of good repair. This indicates that the vehicle may be returned to service, and the defect will be repaired at the next opportunity.

The car house foreperson schedules the repair of deferred defects through a new service request and work order in the MBTA’s enterprise asset management system. The PM inspection is performed by the line superintendent and Quality Department before a car is released and returned to service.

Inspections of MBTA Subway Station Facilities

A routine visual inspection of a subway station is an important part of maintaining safety, functionality, and cleanliness within the station’s infrastructure. It ensures that the station remains safe for both passengers and staff members and that all facilities and equipment are in good working condition.

According to the MBTA’s 2022 Transit Asset Management Plan (TAMP), the MBTA’s Transit Facilities Maintenance Department conducts monthly, quarterly, and annual visual inspections of MBTA stations. Although the MBTA’s TAMP does not specify what components and areas are inspected during a visual inspection, Section 3.1.3 of the American Public Transportation Association’s “Rail Transit Station, Shop, and Yard Inspection and Maintenance” standard states the following:

Routine inspections and maintenance procedures shall be designated for all structural components and equipment, including but not limited to the following:

• tripping hazards
• missing pieces of platform edges or tactile warning strips
• loose sections of overhead concrete
• broken handrails
• cracked stairway nosings
• peeling surface coatings
• defects noted during regular testing of shop equipment
• any other inspectional observation having the potential to cause injury or bodily harm to people
• structural cracks or shifting
• severely corroded structural members
• structural deterioration of platform overhangs
• significant widening of expansion joints
• critical concrete slab protrusions
• falling section of overhead concrete
• significant bulging of platform walls or partitions
• heavy water infiltration
• any other inspection observation having the potential to cause injury or bodily harm, or to generate a costly investment by the transportation provider to remediate the defect

3. According to MBTA officials, in addition to visual inspections, the MBTA uses third-party vendors to perform ultrasonic and optical inspections of track. Ultrasonic inspections use sound waves to detect internal flaws in the track. Optical inspections use a laser to detect defects, wear, and measure track geometry. On August 30, 2023, the MBTA released a report conducted by an independent consultant that covered the ultrasonic and optical inspection processes. To avoid duplicating efforts, we limited the scope of our audit work to only include visual inspections of track conducted by the MBTA, according to the schedule set forth by the Department of Public Utilities. 
    
4. According to the American Public Transportation Association, a nonprofit group of public and private organizations that promotes the interests of public transportation in the United States, heavy rail is an electric railway with the capacity to handle a heavy volume of traffic.
5. According to the American Public Transportation Association, light rail usually handles a smaller volume of passengers.
6. Each MBTA subway line has its own fleet of vehicles.
7. The MBTA performs service, inspections, and repairs on its subway cars at 13 facilities (car houses) located throughout the Commonwealth. 
8. A deferred defect is a problem or issue identified during an inspection that is not immediately addressed or repaired. Instead, the repair of the defect is postponed—deferred—to a later time. 

Date published:	March 10, 2025